1. Field of the Invention
The present invention relates generally to a stereoscopic display requiring no special glasses, and more particularly, to a head tracking three-dimensional (3D) display so adapted that a viewer can properly view a three-dimensional (3D) image even if the head of the viewer moves by detecting the position of the head of the viewer. Further, the present invention relates to a head position detecting device capable of detecting, when the viewer views a 3D image without requiring special glasses, the position of the head of the viewer, to enlarge the stereoscopic area.
2. Description of the Prior Art
As a stereoscopic display requiring no special glasses, a system using a parallax barrier and a system using a lenticular lens have been known. In such a stereoscopic display, however, the stereoscopic area is narrow.
Therefore, a stereoscopic display so adapted as to detect the position of the head of a viewer, to optically make correction depending on the head position has been conventionally known.
In a head tracking stereoscopic display shown in FIG. 31, a right eye image and a left eye image are respectively displayed on liquid crystal display (LCD) panels for image display 701 and 702, a right half image of a viewer which is picked up by an imaging device 703 and an image obtained by negative-positive inversion of the right half image in an image processing device 704 are respectively displayed on viewer image display devices 705 and 706 each composed of an LCD panel for back-light, for example, the viewer image display devices 705 and 706 are respectively used as illuminating devices for displaying right and left eye images, and the right eye image and the left eye image which are synthesized are respectively viewed with only the right eye and the left eye of the viewer, by Fresnel lenses 707 and 708 which have directional properties and a half mirror 709.
Specifically, a portion where a viewer image is displayed in the viewer image display device 705 emits light, so that the light emitting portion becomes right eye illuminating light, while a portion where a viewer image is displayed in the viewer image display device 706 emits light, so that the light emitting portion becomes left eye illuminating light, and the positions of both the light emitting portions are changed by following the position of the viewer. Therefore, the positional limitation of the viewer for stereoscopic view is reduced.
In the above-mentioned conventional head tracking stereoscopic display, an imaging device and the display devices to be a light source are required, however, the structure of a back-light is complicated, and the cost is high.
An example of the conventional head position detecting device is one, having a device mounted on a viewer for producing a magnetic force, adapted so as to detect the position of the viewer by grasping the position where the magnetic force is produced using a magnetic sensor. If the position of the viewer is detected using the magnetic sensor, however, the scale of the head position detecting device becomes large, and the cost thereof becomes comparatively high.